Well if it was "vegetarian" there could be cream, but "vegan" wouldn't have cream. There could still be olive oil or something like that though. Vegetable stew maybe? It would at least give an estimate.

True, but are you really going to trust a chef with the very specific requirements of that diet? I wouldn't. My brother-in-law is a chef and his wife is a vegan, and let me just tell you he would serve her soup with cream in it and not even guess it's not part of her plan. Unless the chef is a vegan, anything goes.